What a clever photo. I used to go to the camera obscura at Garden of the Gods park in Colorado Springs. It is gone now. It was projected onto a white canvas. I never thought of projecting onto the ground. Simply awesome.

See: http://en.wikipedia.org/wiki/Camera_obscura for the details of how a camera obscura projects an image on a canvas - in this case the ground; with rocks, leaves and other debris, which makes for a very granulated canvas.

@Abhinav Singh This is a tent-camera image. A tent is set up and then the camera obscura technique (basically a giant pinhole camera using a periscope type lens) is used to project an image down onto whatever surface the tent is set up over. Then he takes a photo of that projection. It is not the fusion of two images.